Process for the carbonization of rags



April 3, 193.4. K. SCHUBERT A PROCESS FOR THE CARBONIZATION OF RAGSFiled Dec. 31, 1931 w 7 g 9 0 1 Q o u a Q Q: on an a a 0 o a Q a W a Q QP. a m 2 a //1 Q Q Q Q D Q Db EEO a. w j o a L 2 J1 1 J m 3 A [M d m fINVENTOR KARL SCHUBERT By Patented Apr. 3, 1934 UNETED STATES PAT GFFICEPROCESS FOR THE CARBONIZATION OF BAGS Germany Application December 31,1931, Serial No. 584,139 In Germany January 2, 1931 3 Claims.

Various processes are known for the carbonization of rags, that is, theisolation of their animal wool constituents by the destruction of thecotton and other vegetable or cellulosic constituents contained in therags by means of acids and the like. According to the so-called wetcarbonization method, the rags are impregnated with liquid acid, arethereupon freed from excess of acid by centrifuging or by steamtreatment 1 and are then carbonized. This process has not been found tobe particularly satisfactory, chiefly because it requires comparativelymuch time, is expensive and does not always permit the desiredcarbonization effect to be attained in a uniform and certain manner.According to another known process, the rags are treated withhydrochloric acid gas. In such a process, however, there is thedisadvantage of the danger in handling this gas and the difficulty thatthe rags must first be thoroughly and uniformly moistened, sincehydrochloric acid gas alone as such does not act upon the rags.

In practice, therefore, the procedure has generally been first to drythe rags in a so-called 2 carbonization drum and then to carbonize themby introducing acid vapours produced outside the treatment vessel, forexample in a retort. However, even this process which, in itself,undoubtedly leads to satisfactory carbonization effects,

is accompanied by considerable disadvantages and difiiculties, chieflyconsisting in the fact that the acid vapours produced with aconsiderable expenditure of heat and by means of particu larly expensiveapparatus at very high temperatures for example or" about 800 C., havean ex traordinarily corrosive action and thus comparatively very soondestroy the production and treatment apparatus, and are a source ofdanger to the attendants.

It has now been found that all the aforementioned diificulties anddisadvantages may be eliminated and excellent carbonization effects maybe attained with but slight expenditure of material and heat and insimple apparatus, which is practically not subjected to any wear, if therags are first dried in known manner in a carbonizing drum and the acid,for example hydrochloric acid or sulphuric acid, is then introduced intothe heated carbonizing drum in a liquid form and in a finely dividedcondition, for example by injecting it through nozzles. The temperaturesof the treatment within the drum, when for example hydrochloric acid isused as the carbonizing acid, need not in general exceed 140 C. Thisprocess will be explained more particularly hereinafter with referenceto the accompanying drawing wherein Figure 1 shows diagrammatically inplan by way of example an apparatus for carrying out the presentprocess, and

Figure 2 shows the same in cross-section.

After the drum 1 has been made accessible by opening the two covers 2and has been filled with rags, the covers 2 are again closed and the hating device, in this case a gas heating device 3, is set in operation,so as first of all to remove the natural moisture contained in the rags.At the same time, the heated air ascends in the heating chamber l andsweeps round the whole of the outer wall of the chamber 5 containing thedrum 1. The interior of the drum and the rags contained therein arethereby also heated rapidly and the moisture is expelled from the rags.The excess of heating gases can escape through the pipe 6 and theevaporated moisture through the pipe 7. If heating is effectedelectrically or by means of steam, the pipe G may be dispensed with.

When the moisture has been expelled from the rags to a suflicientextent, liquid acid, for example hydrochloric acid, of the ordinarytemperature is injected in a finely divided condition into the drum 1through the nozzle 9 provided in one of the two stub axles 8 of thedrum. The acid is supplied to the nozzle 9 through the con duit 10.

Figure 2 shows by way of example how the acid is led to the nozzle 9.The air compressor 12 is driven by the belt 11, the compressed air isled through the conduit 13 to the acid tank 9O 14 and the acid isthereby forced through the supply conduit 10 to the nozzle 9.Preferably, the acid tank is protected against excessive pressure bymeans of a safety valve 15.

It is quite immaterial in itself what particular method is employed forinjecting the acid, whether for example this is effected by means ofcompressed air or by means of a pump or the like. It is merely essentialthat the acid should reach the interior of the drum in a finely dividedcondition or in the form of a mist. The rags which are in the drum andwhich are continuously mingling with one another by the rotation of thedrum, are thus able to come into uniform and intimate contact with theacid and the reaction between acid and rags can proceed rapidly andcompletely.

Before the introduction of the acid into the drum, the valve 16 of theoutlet pipe 7 is closed, so that the chamber 5 is completely closed andno acid vapours or dust can escape to the outside.

When carbonization is complete, the heating device 3 is shut off,whereupon the temperature falls comparatively quickly and any excess ofacid there may be collects with the cellulose ash on the bottom of thechamber 5, whence it, like the carbonized material from the drum, can beremoved easily and without inconveniencing the attendants.

Example About 100 kilograms of rags are introduced into a carbonizingdrum, perforated like a sieve, which is rotatably mounted within aheating chamber adapted to be suitably heated, for example by means ofgas, steam or electricity, and is provided with an acid injectingdevice, for example a so-called atomizing nozzle, opening within one ofthe stub axles of the drum. The drum and heating chamber are thereuponwell closed, the drum is set in rotation, the air-release valve providedon the apparatus or on the heating chamber is opened, and the heatingdevice is started. After the temperature in the drum has reached about90 to 95 C., and the natural moisture has been driven out of the rags,this being accomplished in about to 1 hour according to the size andtype of the apparatus, the air-release valve is closed, and liquidhydrochloric acid of 22 B. and at the ordinary tem perature is injectedin a finely divided condition into the drum space through the acidinjecting device in an amount of about 8 to 10% by weight of the rags,according to their nature. The temperature within the apparatus havingbeen lowered somewhat by the introduction of the acid, is then raised byfurther heating to preferably about 90 to 140 C., and is maintained atthis point until the carbonization process is completed, which is thecase in A, to 1 hours, according to the nature of the rags and the sizeof the apparatus. The heating installation is then shut off, theair-release valve is opened, and any hydrochloric acid mist which maystill be present is absorbed by filtering apparatus, connected to thecarbonization apparatus. After cooling, which in general does not takemore than hour, the rags which have been carbonized in an excellentmanner with maximum protection to the apparatus material and smallexpenditure of heat and material, are then taken out.

I claim,

1. The process for the carbonization of rags which comprises heatingsaid rags to dry them, treating said dried rags with liquid hydrochloricacid in a finely divided condition, continuing the heating, raising thetemperature or" said heating to a temperature not in excess of 140 C.,continuing the treatment of said rags with liquid hydrochloric acidunder said heat conditions until the rags are carbonized, and separatingthe carbonized rags from the acid.

2. The process for the carbonization of rags which comprises drying saidrags to be carbonized, spraying said dry rags with liquid hydrochloricacid of about 22 B. strength in a finely divided condition, increasingthe heat to a temperature not exceeding 140 C., continuing the sprayingor" said liquid hydrochloric acid under said heat conditions to effectthe carbonization of the rags, cooling the carbonizing rags, andseparating the carbonized rags from the acid.

3. The process for the carbonization of rags which comprises drying therags at a temperature of about 96 C. to about 95 C. for a period of timeextending up to about one hour, injecting liquid hydrochloric acid ofabout 22 Be. strength as a fine spray on said dried rags, raising theheat to a temperature not exceeding 149 C., continuing the injection ofsaid liquid hydrochloric acid under the aforesaid heat conditions for aperiod extending up to about one hour and onehalf until the amount ofinjected hydrochloric acid approximates about 10% of the weight of therags under treatment, cooling the carbonized rags for a period of time,said period being less than one hour, and separating the carbonized ragsfrom the liquid hydrochloric acid.

KARL SCHUBERT.

